Machine



J. C. DRADER Aug. 15, 1961 MACHINE 4 Sheets-Sheet 1 Original Filed Dec.1, 1955 INVENTOR. fi'fj C 741? 7' Aug. 15, 1961 J. c. DRADER 2,995,964

MACHINE Original Filed Dec. 1, 1955 4 Sheets-Sheet 2 w ji TOFNBVS' J. C.DRADEF? Aug. 15, 1961 MACHINE 4 Sheets-Sheet 3 Original Filed Dec. 1,1955 u u m I INVENTOR. 6. j//7@ 7 .JZse

Aug. 15, 1961 J. c. DRADER I 2,9 5,964

MACHINE Original Filed Dec. 1, 1955 4 Sheets-Sheet 4 m if, fi W I x I; IYr 43 ,4 Q Q d R grip IN VEN TOR. Jsc /g 6T J74 7.

United States Patent 2,995,964 MACHINE Joseph C. Drader, Ormond Beach,Fla., assignor to Michigan Tool Company, Detroit, Mich a corporation ofDelaware Continuation of application Ser. No. 550,361, Dec. 1, 1955.This application Aug. 31, 1959, Ser. No. 837,262

2 Claims. (Cl. 80-20) This invention relates to apparatus for formingtoothed elements and, more particularly, to an improved machine forgenerating teeth on toothed elements, such as gears, splines and thelike, and is a continuation of my copending application, Serial No.550,361, filed December 1, 1955, now abandoned.

An object of the invention is to overcome disadvam tages in priormachines of the indicated character and to provide an improved machineincorporating improved means for rapidly generating teeth on toothedelements, such as gears, splines and the like.

Another object of the invention is to provide an improved machine whichfacilitates the formation of teeth on toothed elements with a of time,labor and expense.

Another object of the invention is to provide an improved machine forgenerating teeth on toothed elements incorporating improved means forcontrolling the toothforming tools.

Another object of the invention is to provide an improved machine forgenerating the teeth on toothed elements that is rugged in construction,economical to manufacture and assemble, durable, eflicient and reliablein operation.

Another object of the invention is to increase the speed of productionand improve the quality of toothed elements, such as gears, splines andthe like.

Another object of the invention is to provide an improved machine whichfacilitates the generation of teeth on workpieces without the necessityof cutting or removing material from the workpieces and withoutrequiring prior tooth-forming operations.

The above as well as other objects and advantages of the presentinvention will become apparent from the following description, theappended claims, and the accompanying drawings wherein:

FIGURE 1 is a front elevational view of a machine embodying the presentinvention;

FIG. 2 is an end elevational view of the machine illustrated in FIGURE'1;

FIG. 3 is an enlarged transverse sectional view of a portion of themachine illustrated in FIGURE 1; and

FIG. 4 is an enlarged view, with portions in section, of the tailstockassembly of the machine illustrated in FIGURE 1.

The machine of the present invention facilitates the generation of teethon workpieces without necessitating the cutting or removal of materialfrom the workpieces and without requiring prior tooth-forming operationson the workpieces. In general, the machine of the present invention isadapted to subject a workpiece to the action of a pair of rack-typetools which moves simultaneously in opposite directions. The tools eachhave teeth conjugate to the teeth to be formed on the workpiece, and thetools pressure form teeth on the periphery of the workpiece bydisplacing the metal of the workpiece. Generation of the teeth on theworkpiece may be accomplished when the workpiece is at ambienttemperature or when the workpiece or a portion thereof is heated to anelevated temperature, as by the use of induction heating equipment, andwhen no prior tooth-forming operations have been performed on theworkpiece.

" Referring to the'drawings, 'a machine, generally desig- Patented Aug.15, 1961 nated 10, is shown, embodying the present invention. Themachine 10 is comprised of a lower base 12 and an upper base 14 which isfixed to the lower base 12, as by bolts 16. The lower base 12 and theupper base 14 are preferably heavy and rigid and define an elongatethroat 18 which is generally C-shaped in transverse cross section. Inorder to increase the rigidity of the machine 10, a pair of tie bars 20and 22 are provided, the lower end portions of the tie bars 20 and 22being fixed to the lower base 12 while the upper end portions of the tiebars are fixed to the upper base 14.

A pair of spaced substantially parallel lower slide ways 24 and 26 areprovided which are fixed to the lower base 12, and a pair of spacedsubstantially parallel upper slide ways 28 and 30 are provided which arefixed to the upper base 14. The ways 24 and 26 and the Ways 28 and 30are disposed in vertically spaced confronting relationship in the throat18 of the machine with the bearing surfaces thereof disposed insubstantially parallel planes. A lower slide member 32 is provided whichis mounted for reciprocation on the lower slide ways 24 and 26, and anupper slide member 34 is provided which is mounted for reciprocation onthe upper slide ways 28 and 30, the upper slide member 34 being retainedby a pair of retaining members 36 and 38 fixed to the upper base 14, asby bolts 40.

A pair of tool holders 42 and 44 are provided which are fixed to thelower and upper slide members 32 and 34, respectively. In the embodimentof the invention illustrated, the tool holders 42 and 44 each include abody portion 46 which is fixed to the associated slide member, as bybolts 48. The tool holders 42 and 44 are adapted to retain a pair ofsubstantially identical rack-type toothforming tools 50 and 52 that arefixed to the tool holders 42 and 44, respectively, by bolts 54 whichpass through the tools and the body portion 46 of the tool holders andare retained by nuts 56. For the purposes of the present invention, itis sufficient to state that the tools 50 and 52 are provided with teeth58 on the working faces 60 and 62 thereof. The spacing between theworking faces 60 and 62 of the tools is less than the diameter of theworkpiece 64, or the diameter of that portion of the workpiece uponwhich teeth are to be formed, and the shape of the faces 60 and 62 ofthe tools is impressed or conjugated on the periphery of the workpieceas the tools move relative to the workpiece. The spacing of the workingfaces 60 and 62 0f the tools is regulated so that the depth of theimpression made in the workpiece gradually increases as thetooth-forming operation proceeds, the faces 60 and 62 approaching closertogether in a horizontal plane through the axis of the workpiece as thetools move relative to the workpiece. The taper can be obtained, forexample, by inclining the pitch lines of the tool teeth, by graduallyincreasing the height of the tool teeth while holding the pitch linelevel, or by a combination of the two methods.

In order to facilitate adjusting the distance between the working faces60 and 62 of the tools, each of the tool holders 42 and 44 is providedwith an adjustable gib portion 66 which is inter-posed between the tooland the associated slide member. As shown in FIGURE 1, the gib portion66 of each of the tool holders includes mating sections 68 and 70 havingmating tapering surfaces therebetween. With such a construction,longitudinal movement of one section of the gib portion of each toolholder relative to theother section thereof effects vertical movement ofthe associated tool 50 or 52.

In order to drive the slide members 32 an 34 and, consequently, thetools 50 and 52 simultaneously in opposite directions, a pair ofhydraulic pistonand cylinder units 72 and 74 are provided which arefixed to the lower and upper bases 12 and 14, respectively. Thehydraulic piston and cylinder unit 72 includes a piston rod 76 which 3is fixed to an outwardly projecting portion 77 of the lower slide member32, as at 78, while the piston and cylinder unit 74 includes a pistonrod 80 which is fixed to outwardly projecting portion 82 of the upperslide memberg34, as at 86. The piston and cylinder units -72 end 74 aresubstantially identical in sizeand are con nectedto a common source offluid pressure, such as the hydraulic pump unit 88, by inlet :and outletconduits, such as '90 and92 a suitable control valve being interposedbetween the piston and cylinder units "72 "and 74 and thecornmon sourceof fluid pressure 88 to facilitate controlling the units 72 74simultaneously. Since the pistonand cylinder units 72 and '74 areconnected to a common source of fluid pressure, the slide members 32 and34 are actuated and moved at the same instant and at the same velocity,in opposite directions, the common source of hydraulic pressurehydraulically interlocking the and 74.

"In order to insure the synchronization of the slide members 32 and 34,a pair of driving rack members 94 96 areprovided which are fixed to theslide members 32 and 34, respectively, and which extend in spacedsubstantially parallel relationship with respect to the tools 150 and52, respectively. The driving rack members 94 and-96 mesh simultaneouslywith-a drive gear 98 mounted for rotation on a bracket 100 fixed to aspindle support member 102, the spindle support memberbeing securedtothe 'lower base, as at 104 and 10.6. A Spindle sleeve 108 is providedwhich extends longitudinally of a passageway 110 definedby-the supportmember 102, and the spindle sleeve 108 is keyed to the spindle supportmemberiby a key '112 in order to prevent rotation of the spindle sleeve108 relative to the spindle support member 102. A center 114 is providedwhich is mounted in one end portion of the spindle sleeve 108, thecenter 114 projecting intothe throat of the machine 10 and terminatingat .a position adjacent the tools 50 and 52. In order to facilitateadjusting the center 114, an elongate screw 116 is provided, oneendportion of which threadab-ly engages a nut 118 fixed to the spindlesleeve 108, as by bolts 120. The opposite end portion of the screw 116extends through .a sleeve bearing 122 mounted in an end cap 123. Athrust bearing 124 is provided which engages an annular shoulder 126provided on the screw '116, the assembly being retained by a clampingring '128 which is secured to the support member 102, as by bolts 130.The end portion 132 of the screw 116 projects through the clamping ring128 and is preferably provided with non-circular wrench engagingsurfaces which facilitate turning the screw, as with a wrench. With sucha construction, rotation of the screw 116 in one direction advances thespindle sleeve '108'and the center 114 toward the tools 50 and 52 whilerotation of the screw 116 in the opposite direction retracts the spindlesleeve and the center 114 from the tools 50 and 52. 7

At aposition adjacent the center 114, an end cap 134 is provided whichserves to retain the driving gear 98 and a '136 interposed between thedriving gear and thejln'acket 10.0, the end cap 134 being secured to thebracket 100 by bolts 138.

A lubricant reservoir 140 is provided which is mounted on top of theupper base 14, as viewed in FIG. 1, the lubripant flowing from thereservoir 140 through conduits, such as '142 and 144, which communicatewith ducts, such as 146 and 148, leading to .the bearing surfaces of theupper and lower slide members 32 and 3.4, as well as to the teeth .ofthe driving gear 98 and other bearing suriacesof the machine 10.

A tailstock assembly, generally designated 150, is provided which ismounted on a cantilevered support arm 152,,one end of which is fixed tothe upper 14,-the a m 15 ex ndin outwardly .t cm .11 -u p defini w heqcka se b 11 al o. nc e ails 15 h n ai -u wardly P oisat ssrflansemrfion15. mo nted tor sliding movement 4 on the ways 154, the tailstock beingretained in the selected adjusted position on the ways 154 by screwswhich threadably engage a clamping nut 162. The tailstock 156 alsoincludes a body portion 164, and a tailstock center 166 is providedwhich is mounted in a spindle 168 which extends through the body portion164 of the tailstock and which is supported by bearings 170' and 172.The bearings 170 .and172, in turn, are mounted in a sleeve 174 which ismounted for reciprocation in a bushing 176 carried by the body portion164 of the tailstock, a suitable spacer 17,8 being interposed betweenthe bearings 170 and 172. An end cap member 180 is provided which isfixed to the sleeve 174, as by bolts 182. The cap member 180-is fixed tothe piston rod 184 of a piston and-cylinder unit 186 by a'bolt 188 whichextends through the cap member 180 and threadably engages the piston rod184. The casing 189 of-the unit 186 is secured to the body portion 164of the-tailstock by adapters 190 and 192 interposed between the casing189 and the body portionof the-tailstock. With such a construction,actuation of the pistonandcylinder unit 186 in one direction causes thesleeve 174 and the 'tailstock center 166 to move longitudinally of thetailstock 156 toward the tools 50 and 52, while actuation ofthe pistonand cylinder unit 186 in the opposite direction serves to retract thetailstoekcenter 166 from the workpiece.

The hydraulic piston and cylinder units 72 and 74, and the piston andcylinder unit 186 are controlled by limit switches, such as 194, 196-and198 which, in turn, control electrical circuits which serve to actuatesolenoid valves interposed between the piston and cylinder units and thesource of fluid pressure, thereby actuating th piston and cylinder units72 and 74 and the pistonand cylinder unit 186 as a function of themovement of the slide members 32 and 34 and the tailstock center 166,respectively. I

In the operation of the machine 10, a workpiece 64is inserted in thethroat 18 of the machine with the longitudinal axis of the workpiecealigned with the centers 114 and 166, and the piston and cylinder unit186 is actuated so as to advance the center 166 so that the workpiece:is supported for rotationbetween the centers 114 and 166. The hydraulicpiston and cylinder units 72 and 74 are then actuated so as to drive thetools 50 and 52 simultaneously and at the same speed in oppositedirections. Since the spacing between the working faces 60 and -62 ofthe tools 50 and 52 is less than the diameter of the workpiece, theshape of the faces 60 and 62 ofthe tools is impressed or conjugated onthe periphery of the workpiece. As previously mentioned, the spacingbetween the working faces of the tools is initially adjusted so that thedepth .of the impression made in-the workpiece gradually increases asthe tools move relative to the axis of the .workpiece,.the faces .60 and62 moving closer together in a horizontal plane through the axis oftheworkpiece as the length of-the stroke increases. The end of the strokeis reached when the trailing ends of the-tools pass over the workpiece.It is preferred to remove the workpiece from between the centers beforereturning the tools to .the initialstarting position illustrated inFIGURE 1, the

piston and cylinder unit 186 being actuated to retract the tailstock soas to enable the workpiece to be removed from between the centers afterwhich the hydraulic piston and cylinder units 72 .and 74 are actuated toreturn the tools to the starting position. Another workpiece may thenbe, inserted between thecenters 114 and 166, and the cycle repeated.

While a preferred embodiment of theinvention has been shown anddescribed, it will be understood that various changes .and modificationsmay be made without departmembers mquntesl in spa ed substa t al p ra lr lationship on opposite sides of said workpiece supporting means forrectilinear movement transversely of said axis, each of said slidemembers being adapted to carry a racktype tooth generating tool forsimultaneous engagement with the workpiece, a pair of hydraulic pistonand cylinder units, one of said piston and cylinder units beingconnected to one of said slide members and the other of said piston andcylinder units being connected to the other of said slide members, saidpiston and cylinder units each being connected to a common source offluid pressure 10 for operating said slide members simultaneously inopposite directions, a pair of racks having identical teeth thereon, oneof said racks being fixed to one of said slide members and the other ofsaid racks being fixed to the other of said slide members, and gearmeans mounted for rotation about said axis and meshing with said pair ofracks for synchronizing the movement of said slide members under saidfluid pressure to insure precision meshing of the teeth of thegenerating tool with respect to the teeth being formed on the workpiece.

2. The combination according to claim 1, said workpiece supporting meanscomprising a head center and a tailstock.

References Cited in the file of this patent UNITED STATES PATENTS458,685 Morris Sept. 1, 1891 1,220,369 Slick Mar. 27, 1917 1,622,169Zidovec Mar. 22, 1927 2,584,789 Clark Feb. 5, 1952 2,679,177 Gepfert May25, 1954 FOREIGN PATENTS 898,436 Germany Nov. 30, 1953 942,804 GermanyMay 9, 1956 409,622 Italy Feb. 23, 1945

